Undercarriage legs including units for driving the wheels are known, for example described in application FR 2 954 752. The unit for driving a wheel of the undercarriage leg is carried by a ring that receives the pistons of the brake equipping the wheel.
When the aircraft is on the ground, the undercarriage leg is deformed. In particular, the axle bearing the wheel bends to a non-negligible extent. It is therefore important to be able to take account of this deformation, which may lead to movement of the drive unit relative to the wheel.